Biosensors provide an analysis of a biological fluid, such as whole blood, urine, or saliva. Measuring the concentration of substances in biological fluids is an important tool for the diagnosis and treatment of many medical conditions. For example, the measurement of glucose in body fluids, such as blood, is crucial to the effective treatment of diabetes. The sample of biological fluid may be directly collected or may be a derivative of a biological fluid. Typically, biosensors have a nondisposable measurement device or test meter that is used to analyze the sample of biological fluid that is placed on the test strip.
Many biosensor systems provide calibration information to the measurement device prior to the analysis. The measurement device typically uses this information to adjust the analysis of the biological fluid in response to one or more parameters. The accuracy and precision of the analysis is improved by using the calibration information. If the calibration information is not used, the measurement device may not complete the analysis or may make a wrong analysis of the concentration of the analyte in the biological fluid.
It is common practice in such test meter/test strip systems to ensure proper identification of the test strip in order to ensure proper test results. For example, a single test meter may be able to analyze several different types of test strips, wherein each type of test strip is designed to test for the presence or concentration of a different analyte in the biological fluid. In order to properly conduct the test, the test meter must know which type of test is to be performed for the test strip currently in use.
Also, lot-to-lot variations in the test strips normally require calibration information to be loaded into the test meter in order to ensure accurate test results. A common practice for downloading such calibration information into the test meter is the use of an electronic read-only memory key (ROM key) that is inserted into a corresponding slot or socket of the test meter. Because this calibration data may only be accurate for a particular production lot of test strips, the user is usually asked to confirm that the lot number of the test strip currently in use matches the lot number for which the ROM key was programmed.
Many other instances in which it is desirable to have information relating to the test strip are known to those having skill in the art. Prior art attempts to code information onto the test strip for reading by the test meter have suffered from many problems, including a severely limited amount of information that can be coded and the use of relatively large amounts of test strip surface area for the information coding function.
Thus, a system and method are needed that will allow information to be coded onto a biosensor for reading of the information by the test meter.